From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Four indicator diagrams for a J III rear cylinder, showing high and low pressure performance at various RPMs.
| Identifier | ExFiles\Box 105\3\ scan0266 | |
| Date | 19th July 1932 | |
| Top-Left Diagram: J III REAR. HIGH PRESSURE 19-7-32 VALVE SPRING REPLACED BY DISTANCE PIECE & 5 LB/O" EXT PRESS APPLIED. STANDARD VALVE. 1" STROKE. R.P.M. 540 360 180 90 308 LB/O" 120° I.S. M E P 1ST DIAGRAM Top-Right Diagram: J III REAR. HIGH PRESSURE 19-7-32 VALVE SPRING REPLACED BY DISTANCE PIECE & 5 LB/O" EXT PRESS APPLIED STANDARD VALVE. 1" STROKE. R.P.M. 540 360 180 90 308 LB/O" 120° I.S. 2ND DIAGRAM Bottom-Left Diagram: J III REAR. LOW PRESSURE 19-7-32 VALVE SPRING REPLACED BY DISTANCE PIECE & 5 LB/O" EXT PRESS APPLIED. STANDARD VALVE. 1" STROKE. R.P.M. 540 360 180 90 308 LB/O' 120° I.S. 2ND DIAGRAM Bottom-Right Diagram: J III REAR. LOW PRESSURE 19-7-32 VALVE SPRING REPLACED BY DISTANCE PIECE & 5 LB/O" EXT PRESS APPLIED STANDARD VALVE. 1" STROKE. R.P.M. 540 360 180 90 308 LB/O" 120° I.S. 1ST DIAGRAM | ||